1. Field of the Invention
The present invention relates to an audio signal reproduction apparatus, and more particularly, to scratch playback of a recording medium on which an audio signal is recorded.
2. Related Art
There has already been known scratch playback for generating a unique rhythm by means of consecutively rotating an analog record disk at high or low speed in a forward or backward direction on an analog record player or the like. There has also been put forth a technique capable of effecting scratch playback of an optical disk such as a CD.
JP-A-2001-312857 discloses a device equipped with a jog dial for effecting scratching operation, wherein the rotational direction and speed of the jog dial are detected, and an audio signal—which has been played and stored in memory beforehand—is read and played back in accordance with the detected rotational direction and speed, thereby effecting scratch play.
Specific scratch playback is performed in the following manner. Specifically, an optical disk is reproduced at a speed double (a double speed) an ordinary reproduction speed (a constant speed) by means of an apparatus for reproducing an optical disk, such as a CD, and the thus-reproduced audio data are stored in memory such as DRAM. The memory stores audio data corresponding to, e.g., about ten seconds. When a jog dial has been actuated, the data stored in the memory are read and reproduced in accordance with the rotational direction and speed of the jog dial. The data that have been stored in the memory and correspond to about 10 seconds are taken as five seconds of preceding audio data and five seconds of subsequent audio data. When the jog dial has been actuated in a forward direction (e.g., a clockwise direction), data—which are chronologically subsequent to the present time by the amount of data corresponding to a rotational angle of actuation of the jog dial—are read and reproduced at a speed corresponding to the rotational speed of the jog dial. In contrast, when the jog dial has been actuated in a rearward direction (e.g., a counterclockwise direction), data—which chronologically precede the present time by the amount of data corresponding to the rotational angle of actuation of the jog dial—are read and reproduced at a speed corresponding to the rotational speed of the jog dial.
As mentioned above, the user can output scratch sound even in the case of an optical disk by means of actuating the jog dial. There is also a case where the user desires to output scratch sound by means of actuating a turntable of a conventional analog player. Particularly, the user, such as a disk jockey (DJ) who is proficient in operation for scratching an analog player, may sometimes experience an unusual feeling in producing scratch sound through actuation of the jog dial.
Therefore, in addition to having the jog dial, preferably the apparatus is also equipped with a turntable and supplies a turntable rotary operation signal, thereby enabling output of scratch sound through actuation of the turntable as in the case of the jog dial. As a result, the user can arbitrary select whether to output scratch sound by means of actuation of the jog dial or by means of a turntable whose operation is acclimatized. Thus, a great improvement in operability of the reproduction apparatus is expected.
However, in a case where the jog dial and the turntable coexist and scratch sound is output by means of scratching operation of one of them, the jog dial and the turntable usually differ in size from each other. When scratching operation is detected by a sensor, a difference exists in operation detected signals. Even when the user has performed the same scratching operation, there may be a case where the scratch sound output by means of the jog dial may differ from that output by means of the turntable. Thus, the user's operability is deteriorated. Particularly, the DJ versed in actuation of the turntable encounters difficulty in outputting, through actuation of the jog dial, scratch sound identical with that which would be output through actuation of the turntable. Therefore, the reason for coexistence of the jog dial and the turntable is diminished.